Charge forming device



Dec. 17, 1940. JORGENSEN 2,225,261

CHARGE FORMING DEVI CE Filed April 8, 1955 34 INVENTOR v 50 ls/ne@ z'Jarge/zgen ATTORNEYS Patented Dec. 17, 1940 2,225,261 CHARGE FORMING DEVICE Clarence H. Jorgensen, Anderson, Ind., assignor to General Motors Corporation, corporation of Delaware Detroit, Mich., a

Application April s, 1935, serial No. 15,201 1s claims. (ci. 12s-119) 'I'hisinvention relates to means controlling the fuel mixture ratio supplied by a charge forming device to an internal combustion engine automaticallyso as to provide'a fuel mixture having 5 the correct ratio of fuel and air for all operating conditions.

It 'is well known that Whenpstarting an internal combustion engine when cold, it is necessary sary to have a fuel mixture which is 'rich in fuel content and it is equally well known that when the engine is hot, it can be started on leaner mixtures. It is further well known' that in order to operate satisfactorily when cold, a fuel mixture richer in fuel content must be provided than that which is necessary to enable to engine to operate properly after it has warmed up. It is further well knownV that if a rich fuelmixture is supplied to the engine for starting purposes and the engine fails to re when the engine is cranked for a considerable period, so much fuel would be drawn into the cylinders of the engine without any combustion taking place that'the engine would become flooded with raw fuel. 'Under such circumstances, this excess of raw fuel must be cleaned out before the engine can be started, this being generally accomplished by admission of excess air. It is, therefore, highly desirable to facilitate easy starting to provide some means to prevent the above described flooding from taking place.

In an earlier joint application of the present applicant and Peter J. Jorgens 1,*SerialNo. 585,- 510, a device was disclosed in which automatically operated mechanism was provided for so controlling the operation of an air inlet or choke valve as to produce the desired mixture ratio for all operating conditions, a rich mixture being provided for cold starting which is gradually reduced in fuel content as the engine warms up and means .being also provided'for causing the admission of -air in progressively increasing quantities in the event of prolonged cranking without startingso as to prevent flooding, and means is also disclosed in said earlierapplication which is operative to increase the fuel content in the mixture upon opening of the throttle valve so as to take t tion through the medium of the thermostat in the event of prolonged' cranking and also upon the sudden increase of suction when the engine begins to run. Still further means, operable upon reduction of suction, were provided to move the 5 valve toward closed position to enrich the mixture for acceleration purposes. y

It is the principal object of the present invention to provide means for accomplishing the desired variations iny the fuel mixture ratio above referred to by automatic manipulation of the fuel valve. In carrying out this object ofthe invention, the fuel valve, in the embodiment ofthe invention shown herein, is held open by`a thermostat when the engine is cold and is gradually moved toward its closed position by the thermostat as theI engine temperature increases. This valve is also controlled by the elect of engine suction, the latter being effective to move the valve toward its closed position through the medium of the thermostat in the event that the en-` -gine fails to start immediately so as to prevent ooding and also when the engine rst starts to run, While the fuel valve is adapted to be moved toward open position by another suction controlled means when the suction falls following an opening movement of the throttleto provide a somewhat richer mixturefor acceleration. Of course, on sudden increase in load with the throt-` tle valve in iixed position, there would also be a decrease in engine suction whichA would eect the same movement of the fuel valve and cause an enrichment of the mixture which would be desirable under such operating conditions.

rIfhe means for controlling the fuel valve of the present application are very similar to the means for controlling the air valve of the earlier i application but operate'upon thefuel valve in the reverse manner. By controllingthe fuel valve certain advantages are produced over the control -40 of the air valve.

'Ihe device disclosed and claimed specifically herein is an improvement on the. device disclosed and broadly claimed inthe earlier joint application previously referred to, Serial No. 585,510.

' Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawingwherein a preferred embodi- -ment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a diagrammatic View of a charge forming device in which the present invention is embodied.

Figs. 2 and. 3 are vertical, sectional views 55 through thel control unit, showing the devices for operating the fuel valve which are illustrated diagrammatically in Fig. 1.

Referring to Fig. l, the reference character I indicates a carburetor of the conventional air valve type which is secured to the riser of an intake manifold I2 having a heating chamber or hot spot I4 formed therein through which exhaust gas is adapted to pass in the conventional manner.. The carburetor unit is provided with an attaching flange I6 by which it issecured to the manifold in the conventional way.

As stated above, the carburetor is of the air valve type and is provided with an air inlet I8 a which is controlled by an air valve 20 normally held in its closed position by a spring 22. `The valve is slidable on the stem 24 andfof course, is

adapted to be opened by the effect of engine suction thereon, the valve being progressively opened as the Iengine suction is increased. This valve has the effect not only of controlling the admission of air, but by placing some restriction .upon the admission of air to the carburetor, in#

creases the necessary air velocity for transporting the fuel from the fuel inlet to the4 engine -cylinders. Obviously, the liquidi'uel will precipitate out of .an 'air column if the latter is moving too slowly.

The air inlet I8 is an auxiliary inlet whilev a primary inlet 26 is also provided to supply a relatively small quantity of air at all times, this inlet being of fixed area if desired, or it may be provided with a valve for regulating the admission of air. Fuel is supplied through the connection 28 to a float chamber 38 and is main' tained at a constant level therein by a valve 32 carried by a. oat 34 in the usual conventional manner. Fuel flows from the float chamber 'through the passage 36 to a fuel nozzle 38, which terminates at substantially the point of greatest suction within a Venturi tube 40, which is employed to increase the suction effect at the nozzle outlet as is customary in carburetors of this type. The flow of fuel from the nozzle is controlled by the fuel valve 42 which is operable by the mechanism to be described in detail hereinafter and the quantity of mixture supplied by the carburetor.

is controlled by a throttle valve 44 of the usual type.

The fuel valve 42 is pivotally supported on a lever 48 secured to a shaft 48 which is journalled for rotation in the carburetor housing. The lever 46 is within the carburetor housing and the opposite end of the lever is provided with a stop lug 58 which is adapted to engage a stop screw 52 threaded in the housing and which may be adjusted to limit the closing movement of the fuel valve. The pivotal mounting oi' the'valve 42 is such as to provide a slight degree of-lost motion so that the valvemay seat accurately.

Secured to the shaft 48 outside the carburetor housing is a lever arm 54 which is pivotally connected to a link 56, the latter being pivotally connected to an arm 58, which is secured to a shaft 68 journalled for rotation in the housing 62 of a control unit in which are positioned the thermostat and other devices for operating the fuel valve 42. This housing 62 is flanged at 64 and is adapted to be secured to that portion of the manifold in which the passage I4 for exhaust gas is formed Obviously,V the construction is such that any rotation of the shaft 88 is communicated to the shaft 48 and will result in movement of the fuel valve 42. Connected at one end to the shaft 6D is a bi-metallic thermostat -engine warms up,

`perature would cause a -fully warmed up.

ofA air in exhausting the G6 of the coil type, the free end of which is pivotally connected to a link 58, which is pivotally connected at its upper end to a plate forming one end of a bellows 12 `normally heldin its expanded position by a compression spring 14, received within the bellows. The interior of the bellows 12 communicates with a valve controlled suction passage 16 through which the suction of the intake manifold may be communicated to the interior 'of the bellows, the effective area of this passage being controlled bythe manually adjustable valve 18, which is screwed into the housing 62. Normally, when the device is cold, the parts are in the position shown in Fig. 1. The spring 14, which is stronger'than the force exerted by the thermostat, holds the bellows in its expanded position so as to definitely determine the position of one end` of the coil thermostat 66. The thermostat tends to coil up when cold so that the shaft 60 is positioned-as shown in the drawing, in which position the arm 58 is depressed to move the arm 54 vto the position shown in the drawing with the'fuel valve wide open. As the the thermostat would, of course, expand and aslong as the bellows remains in its expanded position, the increase in temclockwise` movement of the `arm 58, so, that anyvnormal position of the thermostatwith the engineat` a higher temperature would be such as to position the valve 42 in a partially closed position. When the engine has the effect of the thermostat would be to move the valve downwardly to the position which is determined by the stop screw 52.

The action of the engine suctionupon the bellows 12 is utilized to move the valve 42 toward its closed position in the event that the engine does not startto run within a relatively short time after the cranking of the engine begins.

- The engine suction is communicated through the passage and the valve controlled passage 18 to the interior of the bellows as set forth previously and the air within the bellows is slowly drawn out by this suction. However, the flow bellows is Anecessarily very slow, as the valve 18 should be so set as to provide a passage of very small size. With this construction, the bellows does not contract enough to move the valve to closed position until sufllcient time has elapsed for the engine to start normally, but does contract if the cranking operation is prolonged, so as to pull the link 88 upwardly and through the medium ofthe thermostat, the bellows is effective to rotate the shaft En in a clockwise direction so as tomove the valve 42 toward its closed position. This mechanism is provided for the purpose of preventing flooding in the event that the engine `does not start within a very brief period after cranking begins. The bellows eventually will `become effective to completely close the fuel valve, that is, to move itto the'positlon determined by stop screw lill, if the engine fails vto start until the air withinthe bellows is sufficiently exhausted to effect so great a movement of the parts.

It will be understood, also, that when the engine starts to run, the increase in manifold vacuum is very considerable by comparison to the vacuum during cranking.` This increased suction is communicated to the bellows, which resultsin a movement of the f uel valve toward closed position and a leaner mixture is in this way provided, it being desirable to have a leaner mixture after the engine starts to run than during the cranking period.

Means are also provided, as previously indicated, to operate the needle valve to enrich the mixture during the acceleration period. In order to accomplish this purpose, the shaft 60 has secured thereto, inside fthe control unit housa vertical passage 92 which, at its upper end, connects with the suction passage 15.l A piston 94 is slidable within the cylinder 90 and is normally held in its upper, position, as shown in the drawing, by a spring 96 received between the piston and a closure plate 98 at the lower end of cylinder 90. A valve |00 normally closes a port |02 in the piston 84 and is normally held' closed by the spring I 04. This valve permits the piston to have a dash pot action, but is no part-of the present invention.

Obviously, the piston 84 will be moved downward if the pressure above 'the piston is increased and on such movement of the piston the fuel valve will be moved toward open position to increase the fuel content of the mixture. The pressure above the piston 86 is increased upon any drop in the vacuum above the throttle such as.

occurs when the throttle is opened. The high vacuum existingin the intake when the throttle is closed vor partially closed is communicated through passages 15 and 92 to the cylinder 90 and pulls the piston 94 down against the pressure of spring 96. Any reduction in this vacuum will cause the .piston 96 to move upwardly, and force air from the cylinder 80 through the passage 80 increasing the pressure above the piston 80 and forcing it downwardly as previously described.

A copper gasket |I0 is shown as secured be- F tween the housing 62 and the manifold. This gasket is so formed as to extend partially around fthe thermostat so as to facilitate the heating effect thereon, the gasket being heated by direct conductivity and serving to radiate heat to the thermostat. This, however, is a feature which is not covered in the claims of the present application.

In view of the fact that the invention has been l completely described with respect to the diagramfact that the details of construction of the control,

unit form no part of the present invention and are not covered in the claims specifically, it is deemed unnecessary to describe specifically the two Figures 2 and 3 which merely show the 'actual mechanical construction of what is shown diagrammatically in Fig. l. Therefore, i the specific details of construction of this contro unit are not set forth herein.

I claim:

1. In a charge forming device for an internal combustion engine, a fuel valve adapted to be variably adjusted to control the proportions of. fuel and air in the mixture, the combination of means responsive to the temperature of the engine for setting said fuel valve and means responsive to the -suction of the engine Vand i movable independently of the valve for varying.

the setting of said valve as determined by said temperature responsive means.

2. In a charge forming device for an internal combustion engine having an air valve controlling admission of air thereto, a fuel valve adapted to be variably adjusted to control the proportions of fuel and air in the mixture, the combination of means responsive to the temperature of the engine for setting said fuel valve, and means responsive to the acceleration of the engineyfor varying the setting of said fuel valve as determined byA said tempei'ature responsive means.

3. In a charge forming device for an internal combustion engine, a fuel valve adapted to be variably adjusted to control the proportions of fuel and air in the mixture, the combination of means jointly responsive to the intake pressure and engine temperature for setting said fuel valve, and means responsive tov acceleration of the engine for varying the setting of said fuel valve as determined by the rst named means.

4. In a charge forming device for an internal combustion engine, a fuel valve adapted to be variably adjusted to control the proportions of fuel and air in the mixture, thermally responcombustion engine, a fuel Valve adapted to be o variably adjusted to control the proportions of fuel and air in the mixture, the combination of means operable upon an increase in the normalA intake suction to urge the said fuel valve toward closed position, and independent means responsive to a decrease in the normal intake suction to move said fuel valve toward -open position.

6. In a charge forming device for an internal -combustion engine, a fuel valve adapted to be variably adjusted to control the proportions of fuel and air in the mixture, the combination of means responsive to normal intake suction and operable upon anyfincrease in suction to move said fuel valve toward closed position, and a thermostat operable in accordance with engine temperatures and interposed between said fuel valve and said suction responsive means, whereby the latter is operable upon the fuel valve through the medium of the thermostat.

7. In a charge forming device for an internal combustion engine, a fuel valve adapted to be variably adjusted to control the proportions of fuel and air in the mixture, the combination of means responsive to normal intake suction and operable upon any increase in suction to; move said fuel valve `toward closed position, and a thermostat operable in accordance with engine temperatures, said thermostat being interposed between the fuel valve and said suction responsive means and normally tending tobold the fuel valve in open position, whereby the suction responsive meansis operable upon said fuel valve through the medium of the thermostat and thek latter normally opposes the action of said suction operated means.

8. In a charge forming device for an internal combustion engine, a fuel valve adapted to be variably adjusted to control the proportions of fuel and air in the mixture, the combination of means responsive to an increase in normal intake suction for moving the said fuel valve toward closed position, means responsive to the temperature of the engine forretarding' the movementl of said valve when operated by said suction responsive means, and independent means responsive to a decrease in the normal intake suction for moving the fuel valve toward open position.

9. In a charge forming device for an internal combustion engine, a fuel valve operable tocontrol the fuel `mixture ratio, means for shifting said fuel valve to a given position dependent on certain running conditions of the engine, separate means operable upon accelerationlof the engine vfor moving said fuel valve from said given position to increase the fuel content of the mixture, andmeans for restoring said fuel valve to said given position after an interval of time.

10. Means for controlling the fuel to air ratio of the fuel mixture supplied to an internal cornbustion engine during starting, warming up and normal operating conditions comprising a charge forming device having in combination, a fuel valve movable to different positions to vary the fuel mixture ratio, a throttle valve for controlling the quantity of mixture supplied to the engine, and means for changing the position of said fuel valve in accordance with changes in the temperature under which the engine operates, in accordance with changes in the intake suction of the engine brought about by changes in the engine speed and by changes in the position of the throttle valve.

1l. Means for controlling the fuel to air ratio of the fuel mixture supplied to an internal combustion engine during starting, warming up and normal operating conditions comprising a charge forming device having in combination, a fuel valve movable to different positions to vary the fuel mixture ratio, a throttle valve for controlling the quantity of mixture supplied to the engine, means for moving the fuel valve to decrease the fuel content of the mixture upon increase of engine suction or upon increase'in engine temperature, and means to move the fuel l valve to increase the fuel content of the mixture `upon increase of load and upon movement of' -fuel and air in the mixture, a throttlefor regulating the engine speed, means for operating said fuel valve comprising a thermostat responsive to engine temperature. and a suction motor responsive to the suction of the intake passage anterior to said throttle, said thermostat and said suction motor being connected to said fuel valve in series.

13. In a charge forming device for an internal combustion engine, a fuel valve adapted to be variably adjusted to control the proportions of fuel and air in the mixture, means for operating said valve comprising a thermostat responsive to engine temperature, a suction motor responsive to the suction of the intake passage, said thermostat and said suction motor being connected to said fuel valve in series, and a separate suction motor connected directly to the fuel valve.

14. In a charge forming device for an internal combustion engine, a fuel valve adapted to 4be variably adjusted to control theproportions of fuel and air in the mixture, means for `holding the fuel valve fully open to provide a rich mixture for starting the engine, and means for progressively moving the fuel valve toward 'closed position duringthe cranking `of the engine to gradually lean the mixture at a rate dependent on the temperature of the engine and on the perature increases, and a suction operated member connected to the thermostat and operable to move said fuel valve toward closed position through the medium of the thermostat upon increase in engine suction.

16. In a charge forming device for an internal combustion engine, a fuel valve adapted to be variably adjusted to control. the proportions of fuel and air in the mixture, thermostatic means lnormally holding the fuel valve open when the engine is cold and tending to move said fuel valve toward closed position as 4the engine temperature increases, a suction operated member connected to the thermostat `and operable to move said fuel valve toward closed position through the medium of the thermostat upon increase in engine suction, and a second member responsive to engine suction and connected directly to said fuel valve so as to move said fuel valve toward open position upon decrease in engine suction.

17. In a charge forming device for an internal combustion engine, a fuel valve adaptedfto be variably adjusted to control the proportions of fuel and air inthe mixture, thermostatic means normally holding thel fuel valve open when the engine is cold and tending to move said fuel valve toward closed position as the engine temperature increases, a suction operated member connected to the thermostat and operable to move said fuel valve toward closed position through the medium of the thermostat upon increase in engine suction, and means for adjustably determining the rate at `which said valve is moved by engine suction.

18. In an internal combustion engine having an intake and a manifold having a fuel valve, the combination of means jointly responsive to the intake pressure and the engine temperature for setting said fuel valve, and means responsive to the acceleration of the engine for varying the setting of said fuel valve as produced by the first mentioned means.

CLARENCE H. JORGENSEN. 

